Carburetor



C, L. STOKES CARBURETOR April 7, 1931.

Filed May 26, 1924 INVENTOR.

Patented Apr. 7, 1931 UNITED STATES cnanrns Lawnnncn PATENT OFFICE s'roxns, or LOS ANGELES, camroanm, Assmnonmo cua'rrs ZB. camr, 'rnusrnn, or ernncon, rumors CARBUR-ETO R Application filed May 26,

mixture of fuel and air supplied to the engine roviding maxi will normally be 'a mixturemum economy for light 102. and thereafter when heavy loads are put on the engine the fuel will be automatically increased for maximum power.

A further objectof my invention is to provide automatic priming and accelerating means for an engine in conjunction with my carburetor. A v

A further object of my invention isto control the automatic fuel regulation, priming, and accelerating means of my carburetor by the engine induction vacuum.

Thereare many makes of carburetors known at the present time in active-use in which great study has been given to obtain the eflect now shown in my carburetor. Owing to inherent defects in the design the fuel mixtures provided for said-makes of carburetors are invariably too rich for the reason that if said carburetors are set to give a lean mixture throughout a range of gine speeds, the mixture will then be too lean formaximum power. Therefore, in order to get the best average results from saidcarburetors, the same are adjusted to give a rich mixture throughout the range of service demanded of them.

By my invention, I am now enabled to provide an engine with a lean mixture for light loads, and thereafter as the load is increased, I am enabled to automatically increase the richness of the mixture so that the engine will develop maximum power. In other words, if the throttle on my carburetor be set at any givenfposition and the load on the engine be increased or decreased at that throttle opening, the engine will run with 50 maximum economy at light loads and with 1924. Serial lid-115,912.

maximum power as the load reaches its peak.

This I am now enabled to do in a simple manner by apparatus illu'strated in the drawings, in which the same numbers indicate like parts and wherein:

Fig. 1 is a view of the general arrangements of my carburetor attached to an internal combustion engine.

Fig.2 is a vertical section showing the particular arrangements of the parts of my 5 carburetor.

--Fig. 3 is a vertical sectional view along the lines 3-3 of Fig. 2.

Fig. 4 is a view of part of Fig. 2.

\ Fig. 5 is a sectional detail of a novel thermostat shown in Fig. 1. a

Fig. 6 is a sectional view along the lines 6-6 of Fig. 2.

An internal combustion engine 1 has the usual exhaust pipe 2 and inlet manifold 3. T A carburetor 4 is attached to the intake manifold 3, said carburetor being supplied in any wellknown manner with liquid fuel through a pipe 5. The carburetor 4 is provided with the usual throttle valve 6 for controlling the supply of liquid fuel and air to 1 and with a choker valve 7 for priming the engine 1 for starting;

The carburetor 4 is largely of .a conventionaldesign, being constructed with a float chamber 8 containing an annular float 9 which operates the usual needle valve 10 for cutting ofl, or admitting, fuel from 5 and the liquid level in 8 normally stands at the level A-A.

A compensating well .11 receives its liquid fuel from 8 through a calibrated orifice 12 and supplies said fuel to a nozzle 13 responsive to the induction vacuum of 1. i The upper part of 11 is closed and a pipe 13a is led 9o therefrom to a fitting 14 comprising a cover for an accelerating chamber 15 and said chamber contains a flexible diaphragm valve, or bellows, 16 well known to the trade as a sylphon. The upper part of 16 is closed by a cap. 17 which supports a valve 18 for opening and closing one end. of 13a. The upper part of 14 terminates in a sleeve for guiding 18, which sleeve contains a plurality of air ports 19 for admitting atmosphere to The lower part of 16 is closed by a cap 20 13a and 11 when the valve 18 is unseated. A series of small holes 56 are drilled in 52 adapted to seal the chamber 15 air tight and in 20 is placed a fitting 21 containing a downwardly seating check valve 22 and, normally,

check valve 22 is seated tight in 21 with the exception of a very minute leak 23 provided in the seat for 22, the purpose of which will be later described. A pipe 24 is securely coupled to 21 by" a compression nut 25*fo-r apply being taken from the manifold 3 on the engine side of throttle 6.

The chamber 15 receives liquid fuel from 8 through a veryminute leak 25 and the air spacesbetween '8 and 15 are connected through a relatively large port 26.

A cover 27 encloses the top of 8 and renders the same normally air tight except under such conditions as will be later described wherein a predetermined amount of air constantly leaks into 8 through a very minute hole 28 placed in a bend in a fitting 29 adapted to hold an inwardly opening check valve 30, 29 being securely fastened to the outside of 27.

The choker valve 7 may be manually controlled but in addition thereto I prefer to provide automatic choking and accelerating means which comprise a sylph-on 31 held in a casing 32, the upper parts of 31 and 32 being closed by a cap 33 which terminates in a sleeve 34 containinga downwardly seating check valve 35 the seat therefor containing a minute hole 36. The lower part of 31 is closed by a disc 37 to which is attached a forked stem 38 adapted to fit over aratchet 39 fastened to the spindle 40 for operating the choker valve 7 by means of a pin 41. The ratchet comprises a longtooth 42 and a short tooth 43 and the same is firmly fastened on the spindle 40, the other end of 40 containing a fitting 44 to which is attached a spring (not shown) whereby the choker valve 7 is normally held open. as shown in Fig. 2. Any tendency to move 7 from a horizontal position is normally-resisted by the action of said spring.

A pipe 45 is fastened to 34 for applying the engine vacuum to the interior-of 31 by means of a pipe 46 one end of which is fastened to the manifold 3 on the engine side of throttle 6. The other end of 46 leads to a thermostat placed in the exhaust 2, which thermostat comprises a barrel 47 closed at the upper end by a nut 48 and at the lower end by a nut 49 into which latter 46 is fastened. Centrally of 47 on 49 is a boss 50 adapted to be closed by a valve head 51 the stem of which comprises a tube 52 extending through the center of 48 and being held thereon by a nut 53, the upper end of 52 being open to atmosphere. Centrally of 51 a minute hole 54 is drilled which provides communication from the interior of 52.to the interior of 46 and thence through a small hole 55 to the interior of 3.

for a purpose to be later described.

The operation of my carburetor for obtaining a desired ratio of liquid fuel to air which will give maximum economy and maximum power when desired is as follows By referring to Fig. 2 it will beassumed that engine 1 is normally running with the throttle 6 substantially closed, theengine 1.

. thereby unseating the valve 18 and permitting free access of air through 19 and 13a to 11.

In this manner it will be clearly understood that. the amount of fuel supplied through 13 will be solely that which will flow through the orifice 12 into thechamber 11, the rate of feed to 12 and 13 under a high vacuum as described being very small because the vacuum on 13, below the throttle 6, will probably not amount to more than one-half inch of gasoline suction.

While this condition exists, it will be understood that 8 is open t I atmosphere through through the minute hole 28 and in fact 8 is always under atmospheric, or superatmospheric, pressure owing to the action of check valve 30 which, should the action of 16 in contracting cause any degree of vacuum in 8, will open and immediately restore atmospheric pressure to 8.

If now it be assumed th at throttle 6 be onequarter open, the degree of suction applied through 24 will drop to say ten inches of mercury. At the same time the suction on 13 will have increased say to three inches of gasoline. The reduction of vacuum in 24 due to the part opening of 6 causes an expansion by rendering more effective the application of the increased suction to 13 and thereb to 12. This result thereby increases the ow.

of fuel through 12 for the purpose of providing a maximum economy mixture at that throttle opening and the tapered end of valve 18 is arranged to the end, that the opening and closing of 18 shall admit air through 19 to govern the suction applied through 13 to 12 forgiving the desired result this is, as before. stated, maximum economy at light loads and maximum power when required, therefore it is to be understood that I do not limit myself to a straight taper as illustrated but the tapered end of 18 may be turned and consistof a varying number of dilferent tapers, or shoulders, fashioned in any desired manner to control the suction on 12 for the purpose described.

It is well known that a compensating heat will cause the mixture supplied to an engine to get leaner as the engine suction on the nozzle 13 increases.

This is shown and illustrated in the wellknown Zenith carburetor, which normally provides two nozzles, one of which increases its rate of fuel delivery as the engine suction thereon increases. In this manner said Zenith carburetor attains a compensating effect by the use of two nozzles but without obtain-' ing the mixture proportions which I am now enabled to provide through one nozzle. At the same time it is tobe understood that I do not limit myself to the use of one nozzle, inasmuch as I am enabled to efiect like results with any carburetor comprising a compensating well.

If now it be assumed that throttle 6 is substantially closed at idling speeds, and the same be forced wide open for sudden acceleration, the well 11 being normally full to the level AA during idling conditions, the vacuum in 3 will drop z'ero whereupon 16 will expand its full length quickly, due to the sudden opening of 22, and will cut off the supply of air through'19 to 11. There will be allowed however a suflicient air leak aroundthe seat of 18 to provide thatthe sudden increase of suction on 13, due to the sudden opening of 6, will cause well 11 to be quickly emptied and thereafter the compression of air in the upper part of 15, will cause a like compression in the upper part of 8 for forcing an augmented supply of liquid fuel through 12 to prolong the ac- 'celeration until the super-atmospheric pressure in 8 and 15 will .have been reduced to atmospheric pressure. It will be understood that during this compression a slight leak of air will occur outwardly through 28, but 28 is of such small size that the loss of air there: through is not sufficient to substantially affect my desired result.

In this manner it will be seen that my device is very useful for providing an accelerating charge to an engine, the same being a function of its fuel regulating functions and the same is very easily applicable, not alone to the carburetor herein illustrated but also to many other well-known makes of carburetors now on the market.

It will be especially noted that'the supply of fuel in 15, which is maintained through the minute hole 25, remains substantially constant, because the chamber 15 is so designed with respect to the liquid level A A and the passage 26 that the rise of liquid fuel in 15, due to the sudden expansion of 16, will not permit liquid fuel to be forced through 26, there being but a very slight flow of liquid fuel back and forth through the hole 25, but

such flow has not an appreciable eifect' on the liquid level in 8. Of course, it is readily substantially to apparent ing to 15 might also beused in placeof 25, but the size of 25 is such that it is, in effect, a check valve itself.

. It is also possible, when starting the engine 1 to obtain a priming mixture by rapidly opening and closing 6 when the engine 1 is being cranked, because in this manner excess fuel will be forced through 12 for ultimately raising the level and overflowing from 13, but such priming is better accomplished as shown and described in my copending applications S. N. 626,990, filed March 22, 1923, which matured into Patent 1,694,801 issued Dec. 11, 1928, S. N. 644,923 filed June 12, 1923, which matured into Patent 1,750,766 issued March 18,1930, S. N. 67 6,864 filed November 24, 1923, and in another application executed of even date hereof, In

my co-pending application S. N. 67 6,864 filed November 24, 1923, I provide means for automatically closing the choker valve 7 at starting periods and I am now enabled .to adapt the principle therein outlined to good effect for choking and accelerating according to the engine vacuum. In this apparatus as shown in detail in Figs. 3 and 4, I make particular use of the fact thatthe engine vacuum in 3 is low at cranking speeds and very much higher at idling speeds when the engine has fired.

To utilize this knowledge, I provide that the spindle 40 shall extend a certain distance so that 38 and 41 shall surround the ratchet 39 and ,41 shall, particularly, just about touch the short tooth 43 when-the engine is dead. If it be assumed that the engine 1 and exhaust pipe 2 are cold, the valve 51 will be tightly seated on 40 because I provide that 51 and 52 shall be made of a metal having a different coeflicient of expansion to 47 for instance 51 and 52 may be made of the that a check valve inwardly open nickel iron alloy known as invarl, while 47 k is made of brass. Therefore upon cranking the engine 1. a Vacuum of about 8 inches of mercury will be induced in 3 and applied through 55, 46, and 36 to the interior of 31. This vacuum will be slightly reduced by the stream of air flowing through 52 and 54 but not appreciably because of the minute hole 54. This vacuum causes 31 to contract rap-' idly because 35 will lift from its seat,'atmospheric pressure being supplied to the exterior of 31 through a passage 57 joining the interior of 32 with the air inlet of carburetor 4 on the atmosphere side of choker 7. The contraction of 31 causes the pin 41 to actuate the short tooth 43 to the end "that the choker valve 7 substantially closes the air passage 58, whereupon, 18 bein unseated, the high vacuum in 3 is exerte on 13 for supplying an excess of fuel to the'engine 1.

This excess of fuel is sufficientto cause the according to the engine temperature.

position.

' Thereafter, upon further opening of the throttle 6, the vacuum applied to the interior of 31 will be proportionately and slowly reduced because the check valve 35 will be tightly seated and the inflow of air to 31 will be checked by the minute opening 36. Therefore upon the sudden opening of 6, there will be a lag in the opening of 7 and this lag is utilized to induce a higher suction on the nozzle 13 for increasing the accelerating charge to be drawn through 12, it being noted that 16 will expand suddenly due to the position of check valve 22.

At the same time, after providing a priming charge, it will be noted that the position of 7 will normally be wide open when 6 is wide open because, not only will there be substantially the samevacuum on the inside F and outside of 31, due to the passage 57, but 3 also because the spring-like action of 31 tends to normally expand the same to its full length. It should be noted however, that while, under such conditions, the vacuum on the inside and outside of 31 is sub- 5 stantially the same, there exists a slight difference between the vacuum in 58 and 3 sufficient to prevent the return of 41- to its normal position for starting to the end that as long as the engine is running a priming charge will not be induced by the closing of 7 when 6 is suddenly closed.

It will thus be seen that the valve 7 responds to and follows the movement of 6, except that when the engine is first started,

45 the valve 7 will be fully closed for inducing a priming charge to 13. r

This movement is an improvement on m aforementioned application S. N. 676,864, filed November 24, 1923, and in connection therewith I now provide a thermostatic regulator adapted to reduce the movement olf 7 I it be assumed that 1 and 2 are cold, the first priming charge induced by the closing of 7 as described will cause the heat of the ex-.

haust to be applied to 47 which, being made of brass expands rather rapidly because not only are 51 and 52 made of a metal having a low co-efiicient of expansion, but they are further aided in not expanding due to'th c cooling effect of the stream of air passing through 52 and 54 responsive to the vacuum applied through 46.

The expansion of 47 therefore causes an annular space between 51 and 50 whereupon of 31 and governing the same according to the temperature of the gases passing through 2; The effect of this is to cause 7 to perform its priming function and thereafter to be safely regulated for the purpose of not causing too rich a mixture to be induced through 13 when the engine 1 attains a running temperature.

A similar efiect may be obtained, although i in different degree, by eliminating 47 plugging the end of pipe 46 connected thereto, and substituting a'flat strip of by-metallic construction for the stem 38. Such strip would then be adapted to move the pin 41 to and from the center of 39 along the face of 43 to the end that at lower and higher atmospheric and engine temperatures, the pin 41 would cause a greater or less movement of 39 for closing 7.

In other words, such a thermostatic strip would govern the choking effect of 7 according to both atmospheric and engine temperatures.

It should behere understood that the priming and accelerating means co-ordinated in the sylphon 31, the choker 7, and thermostat 47 may be used in conjunction with the accelerating and priming means comprising the well 7 and sylphon 16, or the same may be used separately as desired, the provision being made herein to provide a carburetor having several adaptable devices which may be co-ordinated to give the best results.

In Fig; 6 is illustrated a priming and idling means for the carburetor 4 wherein a chamber 59 is fed with liquid fuel from the acceleratingtwcll 11 and 59 is normally full to the level A--A..

When the throttle 6. is closed, as it usually is at starting position, the engine vacuum in 3 is applied through a pipe 60, which pipe extends substantially to the bottom of 59 below 3 the fuel level A--A and ends a slight distance above a nozzle 61 containing a small orifice 62 adapted to be of such a size as to provide suflicient fuel for causing the engine 1 to idle.

The upper end of 59 is closed airtight an the admission of atmosphere thereto is governed by a valve 63 through a passage 64.

In this manner it willvbeseen that when the engine 1 is cranked, the high vacuum in 3 will cause the liquid fuel in 59 to be rapidly withdrawn thereby assisting the engine to start and this withdrawal of 'fuel from 59,

,terior of 31 thereby reducing the movement due to the atmospheric pressure through 63,

will uncover the lower end of 60 and thereafter sufiicient fuel will be induced by said vacuum through 62 for forming, in conjunction with the air admitted through 63, the

' the pressure in said and the accelerating well 11 is empty, it will be noted that no fuel will be supplied through 62 due to the diversion of the same through 13, but when the engine 1 is dead, liquid fuel will again fill 11 and 59 through 25, 65, and

62 to the-level A-A.

The carburetor 4, as a'unit, may be-used without the auxiliary priming and'accelerating means contained in 32 and it is obvious that all the priming and accelerating means described may be used conjointly, 0r individually, according to any particular-design. It is also obvious that if it is not desired to use 16 for accelerating by placing air pressure on 8, a simple vacuum and spring controlled piston may be substituted for operating the valve 18, in which case the ports 25 and 26 will be closed air tight.

Other forms of thermostatic control may he used to govern the use of 31 and the same may be placed in the'water circulating system of engine 1 or, if 58 is connected to 2 by a hot air pipe, such thermostatic control may be placed therein.

I claim: r

1. In an internal combustion engine, an intake passage, a throttle in said passage, a carburetor for supplying ,an explosive mixture to said engine through said passage, said carburetor comprising a fuel chamber, a compensating well and a nozzle in communication with said chamber, and means for automatically progressively reducing the pressure in said well, by proportionately reducing the amount of air supplied thereto as said throttle is opened at low speeds only.

2.. In a carburetor, a carburetor chamber for mixing air and fuel by suction, a throttle in the chamber, a nozzle for supplying fuel to the chamber, a fuel chamber for supplying fuel to said nozzle, said last named chamber being provided with a fuel inlet, a float controlled valve for said inlet, means governed by said suction for controlling the flow of fuel through the nozzle, said means comprising mechanism for temporarily increasing sudden acceleration of,the engine, and means for automatically controlling the supply of air to said nozzle. v

3. In a carburetor, a mixing chamber for mixing air and fuel by suction, a throttle in the chamber, a nozzle for supplying fuel to the mixing chamber, a fuel reservoir for supplying fuel to the nozzle, a fuel inlet for said fuel reservoir, a float controlled valve for said inlet, a chamber and expansible means therein governed by suction for controlling the flow of fuel through the nozzle, said expansible means in said chamber effecting pressuretherein to effect a temporary increase of fuel chamber during the pressure in said fuel reservoir during the sudden acceleration of the engine and means for automatically controlling the supply of air through said DOZZ16.\

4. In a carburetor, a mixing chamber for mixing air and fuel by suction, a throttle in the chamber, a nozzle -for supplying fuel to the mixing chamber, a fuel reservoir for supplying fuel to the nozzle, a fuel inlet for said fuel reservoir and a float controlled valve for said inlet, a chamber and expansible means therein governed by suction for controlling the flow of fuel through the nozzle, a port connecting said reservoir and said chamber, said expansible -means effecting pressure in said chamber to effect a temporary increase of pressure in said fuel reser- .VOll durlng the sudden acceleratlon of the engine and means for automatically control-' ling the supply of air to said nozzle.

5. In a carburetor, a mixing chamber for mixing air and fuel by suction, a throttle in the chamber, a nozzle for supplying fuel to the mixing chamber, a fuel reservoir for supplying fuel to the nozzle, a fuel inlet for said fuel reservoir and a float controlled valve for said inlet, a chamber and expansible means therein governed by suction for controlling the flow of fuel through the nozzle, an outlet port in said mixing chamber above said throttle and a connection between said port and said expansible means, said means effective to create a temporary increase in pressure in said fuel reservoir during a sudden acceleration of the engine, and means for automatically controlling the supply of air through said nozzle.

6,. In a carburetor, a mixing chamber for mixing air and ,fuel by suction, a throttle in the-chamber, a nozzle for supplying fuel to the mixing chamber, a fuel reservoir for supplying fuel to the nozzle, a chamber and expansible means therein governed by suction for controlling the flow of fuel through the nozzle, a port connecting said reservoir and said chamber above the fuel level in the same, said expansible means effective 'to create a temporary increase in atmospheric pressure in said fuel reservoir during a sudden acceleration of the engine to increase the flow of fuel through said nozzle and means controlled by said expansible means for automatically controlling the supply of air to said nozzle.

7. In a carburetor,a mixing chamber for mixing air and fuel bysuction, a throttle in said chamber controlling said suction, a nozzle for supplying fuel to the mixing chamber, 4

means for controlling the supply of air to said nozzle.

" 8. -In a carburetor, a. mixing chamber for mixing air and fuel by suction, a throttle in said chamber, a nozzle for supplying fuel to themixing chamber, a fuel reservoir for supplying fuel to'the nozzle, expansible means efi'ected by varying degrees of suction for controlling the quantity of fuel flowing,

through the nozzle and means simultaneously controlled by the varying degrees of expansion or contraction of said expansible means for controlling the supply of air through said nozzle.

9. In a carburetor, a mixing chamber for mixing air and fuel by suction, a throttle in said chamber, a nozzle for supplying fuel to the mixing chamber, a fuel reservoir for supplying fuel to the nozzle, a chamber and expansible means therein, a port in said mixing chamber above said throttle and a connection between said port and said expansible means, said means eifected by varying degrees of suction at the port for controlling the quantityof fuel flowing through said port, said expansible means efl'ecting the temporary increase of pressure in the fuel reservoir during a sudden acceleration of the engine and means simultaneously controlled by the varying degrees of expansion or contraction of said expansible means for controlling the su 1y of air to said nozzle.

cigned at Wilmington, in the county of Los Angeles and State of California, this 21st day of March, A. D. 1924.

' CHARLES LAWRENCE STOKES. 

